A table saw is a power tool used to cut a work piece to a desired size or shape. A table saw includes a work surface or table and a circular blade extending up through the table. A person uses a table saw by holding a work piece on the table and feeding it past the spinning blade to make a cut. The table saw is one of the most basic machines used in woodworking.
The blade of a table saw, however, presents a risk of injury to a user of the saw. If the user accidentally places their hand in the path of the blade, or if their hand slips into the blade, then the user could receive a serious injury or amputation. Accidents also happen because of what is called kickback. Kickback may occur when a work piece contacts the downstream edge of the blade as it is being cut. The blade then propels the work piece back toward the user at a high velocity. When this happens, the user's hand may be carried into the blade because of the sudden and unexpected movement of the work piece.
Safety systems or features are often incorporated into table saws to minimize the risk of injury. Probably the most common safety feature is a guard that physically blocks an operator from making contact with the blade. In many cases, guards effectively reduce the risk of injury, however, there are many instances where the nature of the operations to be performed precludes using a guard that completely blocks access to the blade.
Another safety device sometimes incorporated into table saws is a riving knife. A riving knife is a fin-like plate positioned adjacent the rear edge of the saw blade and within the projected kerf and top-to-bottom cutting capacity of the blade. A riving knife functions to keep a work piece from shifting sideways and catching on the rear edge of the blade and being kicked back at the user by the blade. The riving knife is mounted in a table saw so that it remains in a fixed position relative to the blade as the blade tilts and changes elevation.
Some table saws include a spreader or splitter instead of a riving knife. A splitter is a flat plate, similar to a riving knife, but typically extending above the top-to-bottom cutting capacity of the blade so that a blade guard can be mounted thereto. An anti-kickback device such as anti-kickback pawls, which are toothed pawls positioned to oppose a work piece being thrown back toward a user, are often mounted on the splitter. Splitters typically tilt with the blade, but do not move up and down with the blade.
Other safety systems have been developed to detect when a human body contacts a predetermined portion of a machine, such as detecting when a user's hand touches the moving blade on a saw. When that contact is detected, the safety systems react to minimize injury. These systems may be used in conjunction with table saw attachments such as blade guards, riving knives, splitters and anti-kickback pawls.
The present document discloses improved table saws, table saw components, systems to mount and index table saw attachments, and table saw attachments such as riving knives, blade guards, splitters and anti-kickback pawls.